<template>
  <div class="box">
    <div id="nav-icon1" :class="{open:isopen1}" @click="isopen1 = !isopen1">
      <span />
      <span />
      <span />
    </div>
    <div id="nav-icon2" :class="{open:isopen2}" @click="isopen2 = !isopen2">
      <span />
      <span />
      <span />
      <span />
      <span />
      <span />
    </div>
    <div id="nav-icon3" :class="{open:isopen3}" @click="isopen3 = !isopen3">
      <span />
      <span />
      <span />
      <span />
    </div>
    <div id="nav-icon4" :class="{open:isopen4}" @click="isopen4 = !isopen4">
      <span />
      <span />
      <span />
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      isopen1: false,
      isopen2: false,
      isopen3: false,
      isopen4: false
    }
  }
}
</script>

<style scoped lang="scss">
$color:#d3531a;
/* 第一个 */

#nav-icon1, #nav-icon2, #nav-icon3, #nav-icon4 {
  width: 60px;
  height: 45px;
  position: relative;
  margin: 50px auto;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  -webkit-transition: .5s ease-in-out;
  -moz-transition: .5s ease-in-out;
  -o-transition: .5s ease-in-out;
  transition: .5s ease-in-out;
  cursor: pointer;
}

#nav-icon1 span, #nav-icon3 span, #nav-icon4 span {
  display: block;
  position: absolute;
  height: 9px;
  width: 100%;
  background: $color;
  border-radius: 9px;
  opacity: 1;
  left: 0;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  -webkit-transition: .25s ease-in-out;
  -moz-transition: .25s ease-in-out;
  -o-transition: .25s ease-in-out;
  transition: .25s ease-in-out;
}

#nav-icon1 span:nth-child(1) {
  top: 0px;
}

#nav-icon1 span:nth-child(2) {
  top: 18px;
}

#nav-icon1 span:nth-child(3) {
  top: 36px;
}

#nav-icon1.open span:nth-child(1) {
  top: 18px;
  -webkit-transform: rotate(135deg);
  -moz-transform: rotate(135deg);
  -o-transform: rotate(135deg);
  transform: rotate(135deg);
}

#nav-icon1.open span:nth-child(2) {
  opacity: 0;
  left: -60px;
}

#nav-icon1.open span:nth-child(3) {
  top: 18px;
  -webkit-transform: rotate(-135deg);
  -moz-transform: rotate(-135deg);
  -o-transform: rotate(-135deg);
  transform: rotate(-135deg);
}

/* 第二个 */

#nav-icon2 span {
  display: block;
  position: absolute;
  height: 9px;
  width: 50%;
  background: $color;
  opacity: 1;
  -webkit-transform: rotate(0deg);
  -moz-transform: rotate(0deg);
  -o-transform: rotate(0deg);
  transform: rotate(0deg);
  -webkit-transition: .25s ease-in-out;
  -moz-transition: .25s ease-in-out;
  -o-transition: .25s ease-in-out;
  transition: .25s ease-in-out;
}

#nav-icon2 span:nth-child(even) {
  left: 50%;
  border-radius: 0 9px 9px 0;
}

#nav-icon2 span:nth-child(odd) {
  left:0px;
  border-radius: 9px 0 0 9px;
}

#nav-icon2 span:nth-child(1), #nav-icon2 span:nth-child(2) {
  top: 0px;
}

#nav-icon2 span:nth-child(3), #nav-icon2 span:nth-child(4) {
  top: 18px;
}

#nav-icon2 span:nth-child(5), #nav-icon2 span:nth-child(6) {
  top: 36px;
}

#nav-icon2.open span:nth-child(1),#nav-icon2.open span:nth-child(6) {
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}

#nav-icon2.open span:nth-child(2),#nav-icon2.open span:nth-child(5) {
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
}

#nav-icon2.open span:nth-child(1) {
  left: 5px;
  top: 7px;
}

#nav-icon2.open span:nth-child(2) {
  left: calc(50% - 5px);
  top: 7px;
}

#nav-icon2.open span:nth-child(3) {
  left: -50%;
  opacity: 0;
}

#nav-icon2.open span:nth-child(4) {
  left: 100%;
  opacity: 0;
}

#nav-icon2.open span:nth-child(5) {
  left: 5px;
  top: 29px;
}

#nav-icon2.open span:nth-child(6) {
  left: calc(50% - 5px);
  top: 29px;
}

/* 第三个 */

#nav-icon3 span:nth-child(1) {
  top: 0px;
}

#nav-icon3 span:nth-child(2),#nav-icon3 span:nth-child(3) {
  top: 18px;
}

#nav-icon3 span:nth-child(4) {
  top: 36px;
}

#nav-icon3.open span:nth-child(1) {
  top: 18px;
  width: 0%;
  left: 50%;
}

#nav-icon3.open span:nth-child(2) {
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
}

#nav-icon3.open span:nth-child(3) {
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
}

#nav-icon3.open span:nth-child(4) {
  top: 18px;
  width: 0%;
  left: 50%;
}

/* 第四个 */

#nav-icon4 span:nth-child(1) {
  top: 0px;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#nav-icon4 span:nth-child(2) {
  top: 18px;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#nav-icon4 span:nth-child(3) {
  top: 36px;
  -webkit-transform-origin: left center;
  -moz-transform-origin: left center;
  -o-transform-origin: left center;
  transform-origin: left center;
}

#nav-icon4.open span:nth-child(1) {
  -webkit-transform: rotate(45deg);
  -moz-transform: rotate(45deg);
  -o-transform: rotate(45deg);
  transform: rotate(45deg);
  top: -3px;
  left: 8px;
}

#nav-icon4.open span:nth-child(2) {
  width: 0%;
  opacity: 0;
}

#nav-icon4.open span:nth-child(3) {
  -webkit-transform: rotate(-45deg);
  -moz-transform: rotate(-45deg);
  -o-transform: rotate(-45deg);
  transform: rotate(-45deg);
  top: 39px;
  left: 8px;
}
</style>
